Listening Devices: Designing and Making

I have recently been working with the architect Lara Karady, with a view to creating a piece of architecture which engages people with sound. We were given the opportunity to hold a series of sound-related workshops with KS2 and KS3 children and adults at the National Media Museum in Bradford as part of National Science Week. This gave us the ideal chance to develop and test a small scale project which would feed into a final collaborative piece.

For this series of workshops we decided to make wearable ‘listening devices’. These devices would be a kind of micro-architecture that would help us explore our ideas on a small scale, and the feedback from the workshops would provide valuable information for approaching our final design.

We are interested in our connection to listening and the way in which we experience our spatial environment through sound. As we are ‘always already listening’, it can be difficult to achieve a sense of perspective on the way in which we listen. I became interested by the the idea that if these devices would alter or ‘modulate’ the way that we hear then this might enable us to attain some perspective on how we ‘normally’ listen. 

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We drew our main inspiration from early 20th century acoustic listening devices (above) which were developed in between WWI and WWII by the British and Dutch armies in order to anticipate and locate oncoming enemy aircraft outside the visual range. These were the product of the cutting edge of military research, and were only active for a very short window of time before before satellite and radar technology took over.

The devices provide an interesting reference point for this project as they represented a prioritisation of the ear over the eye, and demanded extremely disciplined approaches to listening as users of these devices were highly trained to hear distance, direction, and plane type. To Raviv Ganchrow this represented a, ‘solitary instance within much broader reconfigurations of listening occurring in the late 19th and early 20th century.’ These devices also facilitated a form of listening which challenged notions of space. As Ganchrow argues, by replacing an optic model of viewing with an acoustic model of listening, these structures opened up, ‘a condition in which the close-at-hand and the far-off momentarily coincide.’

Rather than modulating hearing for a preconceived purpose, our devices would, augment, alter or diminish aspects of hearing in order to shed some perspective on how we originally hear; something which is a far more open-ended and less easily definable goal. The fact that our devices would be wearable and not fixed would mean that the ways in which they responded to and were activated by sound could be defined by their users.

intial sketches

intial sketches2

The devices would modulate sound according to specific aspects of our auditory sense, such as the ability to sense direction, the ability to perceive frequency, the ability to hear the distance of an object, or an ability to hear at all. This meant designing devices that would resonate, channel sound, block sound, and amplify sound in certain ways (see preliminary sketches above). The aim was that with their different properties, the devices would allow user to explore their hearing from different angles. As a user worked through the entire set, they could build a cross-referential picture of the ways in which they engage with certain aspects of their hearing.

The plan was to use easily accessible materials that were cost-effective, like card, piping and funnels. Headsets needed to be adjustable for kids and adults, so we decided for the majority of the devices to use ear defenders as an adjustable, ergonomic base which could be ‘hacked’ for purpose. They needed to be relatively sturdy, able to undergo use by several hundred people, and most importantly they needed to be effective. The process of of achieving this, however, was more by intuition than acoustic testing.

In our first making session, we focused on constructing sets of ‘big ears’, which were a direct reference to the military listening devices (see images below). These would collect sounds in front of the listener and focus them toward the ear. They enabled more sound to be heard than normal, and tended to amplify sound which acted to give the illusion of faraway sounds being closer than they are. Having made our first set rather small we had to keep scaling them up until they became effective as the size of a set of the ‘ears’ is directly proportional to the amount of sound that they capture. We also came to realise that size of the device was proportional to the lowest frequency that it could capture. A larger device meant capturing more of the frequency spectrum and therefore hearing in more detail. Owing to this, our final and best par of ‘big ears’ measured just under a metre in aperture. These were the most time intensive of the devices to make as they were made entirely from card and required the design and assembly of a three-dimensional shape. We also had to determine where to locate the ear hole and how they would be worn.


Making sets of ‘big ears’


In the second making session, we made different sets of resonating, sound cancelling and directional listening devices. These used sound defenders as their bases, which we then drilled in order to fix funnels and tubing which would act to affect the sound.

The first set that we made was a ‘large resonator’, made with ear defenders and card-covered funnels which acted to accentuate frequencies around 200-300hz (see picture below right). These were especially effective at picking up tones in the voice. Following this made a set of small resonators, which consisted of a pair of drilled ear defenders with the foam removed. These acted to accentuate frequencies around 900hz, rather like listening to a large shell.

Next we focused on directional hearing, creating a pair of ‘stereo separators’. these consisted of a pair of noise defenders, with funnels attached in line with each ear. These acted to focus the field of hearing for each ear to exclusively left or exclusively right, meaning that a sense of stereo was accentuated, and an ability to hear a sound from hard stereo right or left in both ears was impaired. They also impaired the ability to hear sounds in front of the listener.

The next pair explored ‘selective directional hearing’: funnels were attached to sections of pipe and could be moved by the user or somebody else to focus in on certain sounds (see picture below middle). A novel effect with these was that the stereo field could be swapped around. A downside with both directional pairs is that the noise defenders acted as acoustic enclosures and carried their own resonances which acted to filter the sound somewhat. Finally we kept a pair of ear defenders and stuffed them with extra foam. These had the effect of significantly diminishing one’s hearing.


Top left: ‘large resonators, top right: ‘selective directional hearing’, bottom pictures: materials and assembly

With seven pairs of listening devices complete, the next step was to plan and conduct the workshops. Read about this in my next blog post.